A California high school student was shocked at what she found when she decided to play detective and stop a string of thefts from backpacks during gym class.

Justine Betti said she decided to hide in a locker to see if she could catch the thief in action. She didn’t expect the alleged culprit to be her gym teacher.

After all of the students left the locker room, the teacher stayed behind, rummaged through backpacks and took money, Betti said.

“Something needed to be done. That’s not okay,” she told ABC News’ Sacramento affiliate KXTV. Betti is a sophomore at Linden High School in Linden, Calif., about 60 miles southeast of Sacramento.

Betti decided to hide in the locker again — this time, with a cellphone camera to record what she saw. She set up a second camera in another locker to get two angles.

Once again, she said she saw the teacher go through the bags. Her video shows someone digging through the bags, and one video appears to show the person taking something out of a pink duffel bag.

“I didn’t want to believe that she would do something like that because she was so nice, but then she did it,” Betti said. “It was really scary. I was like, ‘Oh my gosh. I can’t believe I just got this on video.’”

Betti said she kept watching it “over and over” and eventually took the video to her principal with some friends.

“He said that he’ll investigate it and he told us to delete the video, but I had already sent it to my dad,” she said.

The teacher is on administrative leave, according to KXTV. The Linden School District told ABCNews.com that it is investigating the matter.

The teacher has not been identified, but is a 30-year teaching veteran described as a “great teacher” by many students.

we used to have an issue with our gym teacher stealing things from students however, it was not money, he would steal panties and things from the girls locker room.

perhaps things were different when I was in high school but we only changed our clothes for gym, not our underwear... After school sports were different with showers.. anyway.. thats one messed up teacher

Principal told them to destroy potential court evidence? Seems like two people should be charged, one for theft, one for tampering with evidence.

So the head advised her to delete the recording..... wtf???Good thing she sent a copy to her dad. Teachers are supposed to be model figures, and this person is abusing the trust placed on her.

welllll if that's how you spell enough.....

Sounds like a cover up is already in progressed. Schools are the very worst at that.

I fully understand both your points- and I would agree with the Why tell her to delete it? but it is probably somethings we don't know..

..I asked a lawyer about this and this was his reply.

First of all depending on the state that this occurred .. Public such as a cafeteria or the football field (which a locker room is consider private) video taping is admissible in court but private is not at least not without a court permission. It would actually have to be done by Law Enforcement in order to be admissible in court and court approved for the location of the video to be recorded.

The investigation should have been done with Law Enforcement due to some possible problems of the teacher bringing charges against the child that video taped her and the school system.This is partially because normal video taping there are signs that say one is being video taped. (in some states he told me that was illegal video taping someone without consent or prior posting of all activities are being video taped such as a bank or store)

Even though by evidence with looks alone that she is doing the act but in the video there is no confirmation some item was taken by the owners of the bag which should have also been included on the tape.

One major point to note also why there was the suggestion of deletion of the video is this:

Now should she have accidentally recorded a MINOR in a locker room In any form of undress on that tape then she could actually be charged with a serious crime. Also so would her father. We are talking child po rn here which is a serious crime. (he also went on to remark that even if she recorded herself on that tape in the locker room would possibly be considered that) (he also said it is one thing for a professional locker room to be on tape, but this is a High School Locker Room and a FEMALE locker room .... MAJOR RED FLAG FOR RECORDING)

I guess this is why- in most cases police fully document items they think a thief would steal as well as document the numbers on money. Which he also said the easy way to confirm this would have been to take money mark it.. then confront the principle after the theft to check the teacher for theft of the money and it would have confirmed it. (IE taking a picture of the 20$ that was the plant)Instead he said this possibly could backfire if the teacher has a good lawyer.